Electrodeposition of metals.



- No Drawing.

" UNID STATES PENT AUGUST LEUCHTER, on NEW YonK, n. Y.

ELECTRODEPOSITION F METALS.

Specification of Letters Patent.

Application filed February 15, 1912. Serial-No. 677,863.

which the following is a full, Clear, and

act description.

The invention upon which my present application is based, is an improvement in the art of electrotyping or the production of plate copies byelectro-deposition, and resides in a new and useful method or process of effecting the simultaneous deposit of two metals in the form of a composite metal or alloy upon the conducting surface of a mold or other body of which it is desired to obtain a copy or electro.

Electrotypes or electros, as is well known, have usually been obtained by the deposition of metallic copper upon the graphitized or prepared surface of a mold or case from which the sheet or plate, when of suitable thickness is stripped. The objections "to copper electros, arising from the comparative softness and coarseness of grain of that metal when electrolytically produced, have been fully recognized, but the numerous attempts to produce electros of other and harder metals have usually been attended by failure or at least, with results of doubtful practicability and value.

I have succeeded in producing, electrolyticall printing surfaces and electrotypes general y by the simultaneous deposition of two metals in what appears to be an alloy of both, and which are greatly superior to i the ordinary electros, by. reason of their nized as essential to hardness, tensile strength, flexibility, fineness of texture and great durability, but in reaching this result I have found that practical success depends upon themaintenance of conditions and the observance of precautions notadoptedorfrfllowed in previously known processes, and not apparently recogthe attainment of such results.

In the preferred manner of carrying out my invention I use a tank of the ordmary kind with provision for the suspension therein of the mold or other article upon the surface of which the metal is to be de osited. In conjunction with such mold, and its conducting surface as a cathode, I use an anode of nickel, and an electrolyte containing an iron salt, preferably sulfate of iron.

It is well understood by those skilled in this art, that certain definite relations of anode and cathode, particularly with respect to spacing, manner of suspension, and surface'contact with the electrolyte are neces sary for economical and successful operation, and it is of primary importance that all of these should be observed and secured. In addition to this, however, I have found thatit is essential to so determine and adjust the resistance of the bath as a whole Patented May 14:, 1912.

with respect to the impressedelectromotive force of the circuit arbitrarily fixed by practical conditions and limitations, that the effective voltage shall have a value intermediate to the higher voltage necessary for effecting the deposition of nickel, and the lower voltage suitable for the deposition of the iron. These conditions I have found to be obtainable only by using the metal of higher resistance as an anode, and the metal of lower resistance in solution in the electrolyte, and by so making and arranging the anode that its rheostatic effect will reduce the impressed electromotive force to that value, For example, having established in other respects the proper conditions and relations for a given bath, I employ a source of current giving an electromotive force of five volts, and use an anode of nickel having a rheostatic eifect suflicient to reduce the electromotive force to three volts, a value somewhat in excess of that necessary for the deposition of iron and somewhat below that ordinarily necessary for the deposition of nickel, but which under the conditions tial, however,that the iron should at all times predominate in the electrolyte and' .7 v

hence loss of iron by electrolytic action must be compensated for by the addition of fresh solution so as to preserve a substantial preponderance of iron over nickel in the electrolyte. This discovery has proved of the greatest value and importance in the art of producing on a commercial scale, electrotypes of harder metal than copper, for while it is possible to deposit both nickel and iron simultaneously by the. use of either an iron or a nickel anode in-a bath containing nickel or iron respectively in solution, unless the' conditions above prescribed are established and maintained, the action is not capable of being prolonged beyond a limited time, after which the quality of the deposit deteriorates, b reason of the prcponderance of one of tlie constituent metals in the plate, which may become so great as to result in the deposition of one tothe total exclusion of the other.

In practice the nickel suitable for anodes is never pure, and its electrical resistance will depend upon the proportion of other metals or impurities present. The production or selection of the proper composition and form of electrode suitable for the pur-- pose of this invention is a matter well within the skill of those versed in the art.

In the above description of my invention the illustration of specific procedure is confined to nickel and iron. These two metals are the ones which I prefer, and their use involves the most typical or characteristic embodiment of the invention, mainly because of the fact that their resistances to decomposition difl'er so widely. The same conditions 'obtain and the same rules apply, however, to other metals capable of being electrolytically deposited in the form of alloys, and which require currents of dif ferent voltage for their deposition. such cases the metal of higher resistance should beused as or in the anode, and by its predetermined rheost-atic effect reduce the voltage to a value intermediate to those required or suitable for deposition of either metal alone. 1

What I claim is 4 1. The improvement in the art of simultaneously depositing two metals electrolytically upon a conducting surfaceboth of which metals are capable of being plated, whichconsists in using the metal of lower resistance in solution in the electrolyte, forming the anode of the metal of higher resistance and reducing by the rheost-atic Copies of this patent may be obtained i'or In all effect of the anode the elect-romotive force of the current to a value intermediate to the voltages necessary and suitable for the deposition of either metal alone.

2. The improvement in the art of simultaneously depositing nickel and iron electrolytically upon a conducting surface, which consists in using a nickel anode inan elec-' trolyte containing iron in solution, and reducing by the rheostatic effect of the anode the electromotive force of the current to a value intermediate to the voltages necessary and suitable for the deposition of either nickel or iron alone.

3. The improvement in the art of simul taneously depositing two metals electrolytically upon a conducting surface both of which metals are capable of being plated, which consists in using in predominating proportion the metal of lower resistance in solution in the electrolyte, forming the anode of the metal of higher resistance and reducing .by the rheostatic effect of the anode, the electromotive force of the current to a value intermediate to the voltages necessary and suitable for the deposition of either metal alone.

4. The improvement in the art of simultaneously depositing nickel and iron electrolytically upon .aconductingsurface, which consists in using a nickel anode in an electrolyte containing iron and maintaining at all times in the electrolyte a preponderance of the iron.

5. The improvement in the art of simul trolytically upon a conducting surface,

which consists in using a nickel anode in an electrolyte containmg iron, malntaining at alli'times a preponderance of iron in the electrolyte, and eftectingthe deposition of the metals by a currentofia voltage intermediate to that required for the-deposit of nickel alone and that suitable for the deposit of iron alone.

In testimony whereof I afiix my signature in the presence of two subscribing witnesses.

AUGUST LEUCHTER. Witnesses:

M. LAWsoN' DYER, B. R. SANDMAN.

five cents each, by addressing the Commissioner of ratents, Washington, D. C. 

